Production of clonal planting materials from Gracilaria changii and Kappaphycus alvarezii through tissue culture and culture of G-changii explants in airlift photobioreactors

Global demand for seaweed resources has increased due to their emergent use as sources of biopharmaceuticals, nutraceuticals and biofuels. These high-valued products make possible the use of micropropagation techniques that may be more costly than conventional mariculture. This study reports the successful tissue culture of Kappaphycus alvarezii (Doty) Doty ex P. C. Silva and Gracilaria changii (B. Xia & Abbott) Abbott, Zhang and Xia. Callus induction of K. alvarezii was successfully developed following an explant sterilisation protocol. Callus formation and regeneration of K. alvarezii was observed in solidified Provasoli's enriched seawater medium. Different culture conditions such as agar concentration, growth hormones, nutrients, irradiance and enrichment media were investigated to determine the suitable conditions for explant culture of G. changii. Proliferations of adventitious shoots were induced under the most suitable culture conditions. G. changii explants were successfully cultured in airlift photo-bioreactors, with no decrease in the carbohydrate content in the G. changii explants. This micropropagation technique can provide a useful alternative system for seedling production of economically important seaweeds.